14 replies to this topic

[PaulColeman]

I've nearly got my shell ready for blasting. I've removed both wings, both A panels, both outer sills and the rear valance. When it comes back it should be a few pounds lighter once all the rust has gone My question is this... I need to replace both front halves of the floor (I haven't cut them out yet) and I'm wondering how much more I dare cut out of this shell before it twists. So, what's the collective opinion on this? Will I be okay to cut one side of the floor out at a time and replace without having to brace it? If I can avoid bracing I'd rather, because I don't have anything to hand that I could use.

Thanks, Paul.

[sledgehammer]

Hi
I would brace it if you can , especially if you are doing a large section
at the least take some measurements before you start
it is just as important to make sure the shell is sitting level
and try not to concentrate heat in one area when welding
on small areas , use a quenching rag to avoid heat build up
also take note of where you are sat - make sure you aren't bending the floor downwards when welding it
I have made all the above mistakes in the past
best of luck ... & take your time

[PaulColeman]

Okay, thanks for the tips I'll sit the shell on the garage floor when I weld them in. What's the best way to do it - should I try butt welding it or should I have the new panel overlap the hole? What's the story on the MOT do replacement panels have to be seam welded?

I was planning on using my compressor to blow cold air on the areas I weld to try and stop them warping and then moving around the panel randomly.

Thanks, Paul.

[panelbeaterpeter]

If you're doing the floor in one go, which would make a neater job, I'd brace it. you can do a side at a time without bracing, so long as you keep the cross member in place to use as a guide.

[PaulColeman]

Yes the cross member is staying put I don't have any plans to replace it. I'm just looking at replacing the floors forward of the cross member. I don't know whether to joggle the edge of the replacement floor panel and then overlap the two or butt weld them?

Paul.

[panelbeaterpeter]

Where were you thinking of joining it? in the middle of the cross member? I'd butt weld, and plug weld along the front and to the cross member as per factory. If you want to joggle and overlap, you need to weld both sides. If you butt weld, make sure penetration is good and go easy on the grinding.

[skoughi]

I wouldn't quench or cool down your welds with a blow gun unless it's just tacks. If you quench your welds then you'll shrink them and harden them at the same time. This'll put more distortion in your panels. Do short welds here and there, trying to spread the heat evenly about the repair then let the metal cool down on its own. I would suggest joggling the joins, but a butt weld removes a lap join that might harbour rust. If you do a lap join then drill and spot weld one side then do stich welds on the other side but join them up to make a continuous seam weld

[PaulColeman]

Okay, thanks for the info.

I hadn't thought about where to actually join the floors to be honest as I haven't even offered them up yet to figure out how big they are.

What is the MOT man going to be looking for? He can't take up the carpets and look inside but underneath do all repairs have to be a continuous seam weld? Would plug welds on the outer sills be acceptable or does the sill need to be seam welded where it joins the floor?

Thanks, Paul.

Edited by PaulColeman, 26 October 2011 - 08:18 PM.

[panelbeaterpeter]

Seam weld all repairs apart from areas which can be welded as per factory spec, for example where the floor pan meets the front bulkhead, that is spot welded, so plug welds there are fine.

[midridge2]

sorry pete but that would be a fail if spotted, if you fit a full new panel you can spot weld and or continious weld, but if you put in a repair/part panel eg, a front floor then it has to be continious welded, no spots.

Edited by midridge2, 27 October 2011 - 06:50 AM.

[PaulColeman]

So let me get this straight... if I replace a section of the floor it has to be seam welded all the way around - that's what I thought was the case. But if I replace the outer sill I'm okay to plug weld that on - or does it have to be seam welded where it touches the floor (i.e. inbetween the 6 vents)?

Thanks, Paul.

[Shifty]

My understanding was the same as petes. Its ok to replicate the joints as they left the factory. Any non original joint has to be seam welded.

Otherwise, for example, a door step section would have to be seam welded on all four sides. As it left the factory inner sill edge and the outer sill edge would have been spot welded. As I understand it the two outer edges need to be seam welded where they meet the old door step and then the sill edges can be spot or plug welded to replicate the factory job.

[midridge2]

if you replace a full factory fitted panel then you can spot or weld or a mixture of both,if you fit a repair panel then it has to be continious weld.
in the above example by shifty, a door step is a repair panel because the factory panel was the full door aperture, so to keep it up to mot standard it should be continious welded on all 4 sides.

in most cases joints are seam sealed when a repair panel is fitted so the inspector cannot tell if its spot ot continious welded and passes it.

once this is understood people should be able to understand what needs to be welded and then no dissapointments sp if the mot onspector fails it and it then has to be rewelded spoiling that new paintwork.

regards the sill, because its a full original factory shape panel you can mix spot/plug and continious weld.

Edited by midridge2, 27 October 2011 - 10:13 AM.

[midridge2]

spot welded joints are acceptable where the original panel has been replaced to an existing spot welded flange (provided the original defective panel flange has been removed). Stitch or plug welding is acceptable as an alternative to spot welding in these cases.
this is taken from the testers manual.

the important bit is "where the original panel has been replaced to a existing spot welded flange" this means a full factory style panel, so in the case of a front floor repair panel this is NOT a factory style panel.

[PaulColeman]

Okay, thanks guys.

Cheers, Paul.